Power spectral density measurement for large aspheric surfaces

Testing and evaluating the quality of optical components is a key factor to ensure the safe and normal running of the whole optical system. Based on summarizing the advantages and disadvantages of general parameters which are used in aspheric surface testing, the composing of system, principle in working and the design of related software about Power Spectral Density (PSD) in testing large aspheric surface are explored in this article. In PSD calculation, system transfer function is introduced to correct the measured value for reducing the effect of system error. The test result indicates that PSD can reveal the spatial frequency distribution of wavefront aberration by using large aperture phase shifting interferometer to test the wavefront. And this can be applied as the evaluation standard in testing the quality of optical components. This paper describes the testing results of optical components in size 64mm×64mm, its effective frequency band is 0.03mm-1～3.87mm-1 and rms is 0.0064λ.